I’ve purchased a book from Kobo before. It used the epub DRM compatible with adobe digital editions. At the time (afaik) they didn’t have a way to load it on a kindle without breaking the drm, converting it to mobi and doing a manual transfer. These days I stick with my public library (which uses overdrive and in my opinion is fantastic) or amazon in the event they don’t own ebook licenses.
That's my flow actually. I look up books on Goodreads or Amazon but buy them from Kobo. There are the additional steps of downloading, removing the DRM and uploading it to my Kindle but I think it's worth it.
